Scientists Discover Mosquito's 'Nose'

Nov. 29

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It might seem surprising that a mosquito can smell at all, since it has no nose. But it uses its antennae to smell, and the genes discovered by the researchers are expressed only in the antennae, further evidence of their role.

Opening the Door

Only the female mosquito bites humans, because it needs blood for its reproductive process, and it has developed an uncanny ability to find us. In addition to the body odors and carbon dioxide that we exhale, it also uses sight to detect movement, and it can sense infrared radiation, which suggests that a warm body is present.

But of those various skills, the sense of smell is apparently the most important. Studies have shown, for example, that simply taking a shower will reduce a person's vulnerability to mosquitoes. What they relish is the smell of humans, the "cloud of chemicals" that follows us around, as Zwiebel puts it.

Identifying the genes that make it possible for mosquitoes to discriminate among various odors has "opened the door to designing specific chemicals that would throw a very good monkey wrench into their machinery," he says.

Ideally, that chemical should make any mosquito that sniffs a human gag on the stench and look for dinner elsewhere.

It will take awhile, probably at least several years, to come up with such a chemical, but the playing field may have tipped in the favor of humans.

If so, what Zwiebel and his colleagues are calling the "ultimate bioterrorist" is in for a heap of trouble.

Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.